Piston ring joint



Sept. 7,1937.l C. c. FARMER 2,092,413

- PIsToN RING JOINT Filed June 22, 1934 Figi.

6 4 ATTORN v f iL-"UNITED;STATE'SJPATENT.OFFICE f f tongue of the jointirsftriangular-in` cross lsection.` iIt is understood that, until'thev ring Wears sufl- 3"}2,`09Z,4`13\ o i 1 j `PlstloN RING JoN'r 1 y n CIydecJFarmer, Pittsburgh, Pa., assignor to The` 1 i i -WestinghouseAir Brake Company, Wilmeliing, n Pa.,`a corporation of `Pennsylvania n Application June 22, 1934, Serial No.731,813 v l v -s Claims.` gcl; 3094-46) n n n n, n n Thisinvention relates to `pistonrings and more One object `of-my inventiontis to provide an particularly ,toisplitapistodrings of the step out n improved lap joint'pistonring'of the above charn' d t, v 1 l, acter in'which the Astrength-'of the outside tongue l, n InPatent-ifm.` `1,984,389 issued :to `Oscar S. -is greater than in rings constructedin "accord- McCurdy,Decen 1beri18, 19M-apistoniringfof the-` -ancerwith the above imentioned patent,` and, 5` `above type yis disclosed in which the joint is therefore less liable to become "broken `in air formed t by cutting, l away l the` nfring;` Amaterial .compressor service. f 'n obliquely at the ends of `the ring in a-transverse` attain this object by changingthe angle of directiongtherebyforming on: both -ends "ofthe the cooperating oblique sealingsurfaces ofthe Cio" ring;` atongue; having an `oblique sealing surface,` ring joint,A so that, instead of said surfaces inter- `10 i the sealingsurface on onetongue being'` adapted secting Vthe wearing face'of the ring, they interto slidabiy engage thaton-ithe othertongueso sect the side of the ring a'slight distancetoward n as to provide aleak-proof joint when-the ring is i the center of the ring `from thewearingV `face `in` the co,impressed` or working; condition, the` thereof. n Bythis construction: I" increase the 1 15 l Obliquity ofthecutthrough the ring-toformsaid` cross sectional area,` andthereby th'estengthto 15 ,n tonguesuheing so arrangedthat the outermost resist breakage; of theouter tongueoffthe joint.`

n Accordingto the eonstructionldisclosedinthe -`fciently for the oblique sealing surfaces of the above `rnentione'd` vnloatent,` the` oblique sealing joint tomeetl the wearingfface of thering,"there` ,""ia'ces `ofthe two tongues of the ringjoint inter- "iwill bel slight leakage,` through the `clearance `20 n sect lone side ofthe ring ata linenspacedirom l-"spa `:eprovided betweenftheendsy of theringadthe"`innerxcircumference of theiing/a-distance fjacentthewearing `face.` The shortestdistance` equal `to 0.2 of the depth of the ringarid intersect *fro'mfthe wearing-surface" of "the" ringV tothe im the outer circumference on working facey of the robliquesurfaeesisso jcalculatedifhowever, that "3 ring" at a distance-fromthe opposite sideequal `,before appreciable` leakage may develop between o" 01.2`ofthe width of` the )working faceof the 'the ends of theiringjthe.obliquesurfaceWi11 `meet ings and 1the surfaces oftthe obliqueii sealing the wearing s uriaceso thatleakage` willthenmbe 'aces are eylindricalgin the direction lofi the 4effectively prevented"` during n further wean" In lengthfof the ringQsothatwhenfthefring jointis i other words, according'to niyinvention, Ipro-V i Jtelosed thereiis,` no opening through the joint to J lvidea piston ringfhaving anobliqu'e sealingfjoint30 Y Cil `nerrnit leakage ofiuidqunder,pressure frorn one inwhich the outer-tongue'ofthe joint is strong side to the other even after the ringhas become to resist breakage,` and `in lvi'rhich,m when new,

i g ,tvorn and the` ends consequently :separated to leakage is controlledby theslight clearance space,

, takewup,such-wear.- between the ends` ofthe ring,` and` further' in "35 Rings having joints of the above charactenare which, after slight wear,` leakagelpastfthe ring 3U ,highiyemient in pieventi'ngleakage` in fluid `i'seffectiiely prevented bythe joint.

@is liable tocause sueh` devices to faili to ioperata heretofore beeniproposed to provide fa" fllletfbe-` l;

andjn `View of this high veiciencvdt is proposed tween vthe diagonalsealing surface of thetongues i touse rings having,asimilarwjoint in air colnand thev main' body portion oftheringat the in- 40 piessor pistons. o i, L 'i ner endof saidsealing surface, and such lllet- In ringsof above type,` theoutside tongue vhas been "formed, with a single ,large radius.` @of the. joint is initially relatively-weakasicom- While va llet formed with such a` radius `prol 1 pared othe portion of the ring back of the joint, vides the `desired strengthening of l the tonguesr ".j andduo to theangularity ofthe coacting sealing to resist breakage, such `strengtl'iening is obn surfaces ot the` two tongues of the joint,4 the tained atl the expense `of `the life of the4 ring, cross sectional area, and therefore the strength, *since the large radius reduces thearea of the pressure'hraketdevices wherekeven slight leakage C rIn" rings of thev type above dfescriloed;` it" has` n of the outside tongue reduces rapidlyas the ring diagonalfsurfaces of the ring joint iin bearing im,"wears.,` This fentureis` objectionable-finrings for contact, and'consequently, after sorne wear `takes o an' compressors-,tor in air compressor service, fplace; said diagonal surfaces` move out of beari u the are subject toi hard usage? and wear f ing Contact and thereby renderthe ringuntfor atxdit isundesrable thattheoutertongue should further use, although,'thefthieknesslofjthe `ring become so weakened, dueto wear, 'as to be liable has n ot been reduced, due tou wear, to such an 11 i to break oli andithen cause damage to the comextent `that the ring needbe discarded.V '5- n presser. i i Another object of my inventionis to provide` a. ring jointof the above character having an improved fillet, between the diagonal sealing surface of the tongues and the main body portion of the ring at the inner end of said scaling surface. which is adapted to provide the strength to resist breakage of the tongues equal to that obtained with the large radius fillet heretofore employed, but which is so formed as to provide for a. longer life of the ring than heretofore obtained.

with rings having the ordinary large radius fillet'.

In fitting piston rings to a cylinder, a certain clearance space is provided between the ends of the ring, so that in rings having a diagonal sealing joint and a strengthening fillet, such as above described, it is useless, and involves unnecessary refinement and expense to form thev end of the tongues to t the fillets, although it is desirable that the tongues should not engage the fillets when the ring joint is fully closed.

Another object of my invention is to provide :i lap joint piston ring of the character in which a strengthening fillet is provided between the diagonal sealing surface of the tongues and the f main body portion of the ring, and in which the diagonal edge at the end of the tongues is beveled, so that said ends will not engage said fillets when the ring joint is fully closed.

Other objects and advantages of my invention will be apparent from the following more detailed description of the invention.

In ilie accompanying drawing; Fig. 1 is an elcpear applied to a piston vmounted in acylinder; i `Fig. 5 is an enlarged view of a portion of a ring showing across section of my improved ring joint; and Fig. 6 is an enlarged view of a portion of the ring joint looking at the edge of the ring and with the complementary portions of the joint shown in working relation. f

As shownin the drawing, the ring is ofthe type having a wearing face I adapted to `engage the wall of a cylinder, sidefaces 2 and 3 adapted to slidably engage the side walls of a groove in a piston and an inner circumferential face 4. The joint between the two endsl of the ring is formed by the sliding engagement of an inner tongue 5 on one rend of the ring and an outer and complernentary tongue S on the other end of the ring.

'The tongue 6 is.formed by cutting away the metal of the end of the ring to a diagonal plane `I while the tongue 5 is formed by cutting away the metalof the other end of the ring to said diagonal plane, these two cuts being so arranged that when the ring is compressed to fit a cylinder,

, the tongues 5 and 6 t over each other, with the diagonal surface 8 of one tongue engaging the diagonal surface 9 of the other tongue to form a leak-proof seal.

and 9 which will remain leak-proof upon wear of the ring and consequent separation of the ends of the ring so 'long as said diagonal surfaces remain in contact. This construction is fully described in the aforementioned patent, in view of which, it is not deemed necessary to provide a more detailed description in the present application.

According to the invention the diagonal plane 1 representing the plane of engagement between the surfaces 8 and S intersects the side 3 of the ring at a line spaced from the inner circumferential face 4 of the ring a distance such as A, while said plane intersects the side 2 of the ring at a line spaced from the wearing face I of the ring a distance such as B. By this construction I obtain a relatively large cross section of inaterial in the outer tongue 6 of the ring, as indicated by the section of metal at the left hand side of the diagonal plane I in Figs. 4 and 5,l and as compared to the section of metal obtained in the corresponding tongue in a construction such as disclosed in the aforementioned patent. In Fig. 5 I have shown by a dash line I2 the disposition of the diagonal sealing surfaces of a joint constructed in accordance with the aforementioned patent in order to show clearly the gain in metal and therefore strength of the outer tongue 6 when the joint is constructed in accordance with my invention, such gain being represented by the area of metal lying between the line I2 and plane 1.

When a new ring is installed in a piston there is a slight clearance provided between the ends of the .ring at the joint to allow for expansion of the ring, such clearance being indicated by the reference numeral I3 in Figs. 2 and 3, and it will be evident that until the outer circumferential face I ofthe ring wears down to the surface I4 indicated in Fig. 5, there will be a direct, though very small, leakage path through the ring. When the ring becomes worn to surface I4 however, the edge I5 of tongue 5 will engage the wall of the cylinder and thereby close said leakage path, sov that thereafter the ring will function to provide a leak-proof seal in the same ymanner as that disclosed in the aforementioned patent,. and it should be noted that the distance B is so arranged that edge I5 of the inner tongue will obtain bearing against the wall of a cylinder before the leakage path by way of clearance I3 has become sufficiently large to permit appreciable leakage.

It will be notedl that by the above construction, a stronger outer tongue is obtained than with the construction disclosed in the pending application, and while in this construction a direct leakage path is obtained until the ring wears down slightly, the joint is so designed that edge I5 of the inner tongue 5 of the joint will obtain bearing on the cylinder wall before such leakage becomes appreciable, and it will be further noted, that after such wear has occurred as to bring edge I5 oftongue 6 into engagement with the cylindcr wall the cross sectional arca and therefore the strength of the outer tongue 6 is still substantially the same as said tongue in a new ring constructed in accordance with the aforementioned patent.

In forming the tongues 5v and 6 of the ring joint as hereinbefore described, strengthening fillets I0 and II are formed between the diagonal sealing surfaces 8 and 9 and the adjacent surfaces IB and I1, respectively, of the ring. In addition, the diagonal edge on the end of the tongues ticularfconstruction of the portion of r and 6 is `cut away to provide `beveled surfaces so that when thering VFigi 6 discloses, onv4 'an'jenlarged' scale,v theA par'- n l of the ring'has p l not engage o i closed. With prior constructions of fillet, such as `indicated by the dash contour line l2, the di- `agonal edge of tongue 6 had to be cut back on the have increased the o o areaof each of the diagonal surfaces 8and i) I `by the distance G, which increases the expansive `life of the ring,

so that the following the desired strengthening of'tongue B to resist breakage, while the radius D is `relatively short o and provides a smooth unbroken contour for the `llet I0 between thelongv radius C and thesurface I6 of the ring, it being noted that the contour formed by these two radii approximates that of a quarter of an ellipse. i g o The center from `which the radius C is struck is so selected that the contour of fillet` Ill` is substantiallyftangent with the diagonalsurface 8 'at the line E, the distance between line E and. surface I6 of the ring being less than the length of radius C. `If the contourof the fillet `Il) were formed with one long radius, such as radius C, as used in priorconstructions, the contour of fillet I0 would be in the form of a quarter circle as indicated by the dash line I2,`,and therefore tangent tothe diagonal surface 8 at the line F.

`Thebevel.` |9on tongue 6 intersects the diagonal surface 9 of said tongue at a line 20 which is disposed back of the radial end face of the` tongue a distance at least equalto that between `a beveled surface `on the end of each tongue desurface I6 and tangent line E, and said bevel `is` formed at such anangle that the tongue 6 will fillet I0 when the ring joint is fully p o diagonal surface 9 a distance beyond the line 20 equal to the distance G, in order to prevent engagement of the end of the tongue with thefillet when the joint was fully closed. It will therefore be noted that, according to my construction, I` length of the effective bearing` due to peripheral wear, by a dis-` 2G, and this increase in the life tance equal to beenobtained without any sacrii fice in the strengthening effect of fillet IIJ to preto i 1 `claim as new and vent breakage of tongue 5. i

`While one illustrative embodiment of the invention has been described in detail, it is not my intention `to limitlits scopeto that embodiment or otherwise than bythe terms ofthe appended claims.

ent, is:

. o 1. A` packing ring joint consisting of two com? i plementary tongues having overlapping and slidably engaging sealing surfaces, `a fillet at` the V y junction of each ofsaidfsurfaces with the main bodyportion of the ring,

and a beveled surface on the end of each tongue designed to clear the fillet when the ring is fully closed. i

2. A packing ring joint consisting of two come `pleinentary tongues havingA diagonally disposed,`

overlapping andA slidably i o faces, a fillet at theljunction of each `ofsaid surfaces with`the main body portion of the ring,

and a beveled surface on i o o `ing ,jointw @including llet l0 and bevel I9 whichjis identical with `that'ribntion including'illetl l and bevel |8,""" description of one .portionv @will apply equally `to the other portion.

of said sealing surface,land a a beveled `surface Having now described my invention, what `I n desire to secure by `Letters Pati engaging sealing surthe end of each tongue.'

closed.

` 3. A packingl ring` joint'censisting of twocomplementary. tongues` having diagonally disposed,

overlapping andslidably` .engaging sealing sur- Afa`ces,'a

fillet at the junction of each of said surfaces Vwith the mainbodjf` portion of the ring, and a beveled surface'on the endE of each tongue designed to" clear the fillet 4,WhenQthe ring` is fully closed, the contour of each of said fillets being formed with a large radiusterminating at one end substantially tangent to the sealing surface, and a smaller radius joined substantially tangentiallyto the large radius and to the main body portion of the ring adjacent the inner end of said sealing surface. i

4. A packing ring joint consisting of two complementary tongues having diagonally disposed,

engaging sealing Asurlipse withthe major to the diagonal sealing surface and the minor radiussubstantially tangent to the main body portion of the ring adjacent the inner end of the' sealing surface.`

- 5. A packing ring joint consisting of twocomplernentary tongues having diagonally disposed,

overlapping and `slidably `engaging sealing sura fillet at the junction of` eachof said surwith the main body portion of the ring, and

signed to clear the fillet when the ring isfully closed, the contour of each of said fillets being formed with a large radiusl terminating at one end at substantially the line of tangency with o the diagonalsealing surface and swung from a pivot point spaced, a less distance than the length of said radius, from the surface on,r the main body portion of the ring adjacent the inner end necting the'large radius to i said surface on the main body portion of the ring adjacent the inner end of said sealing surface.

i '6. A packingyring joint consisting of two complementary tongues having diagonally disposed, overlapping and slidably `engaging sealing sur-` faces, a llet at the junction of each of said surfaces with the main body portion of the ring, and

designed to clear the fillet when the ring is fully closed, each of said llets having a portion merging with the diagonal sealing surface the contour of whichhas a relatively long radius of curvature, and a portion merging with theA radial surface of the joint the contour of which has a` relatively short radius of curvature.

'7.` A piston packing comprising an expansible ring having complementary tongues with overlapping and slidably engaging sealing surfaces out diagonally through the ring from one side faceto the opposite side face, the line at which the ring being spaced at such distance from the cylsealing surfaces meet one side face `of the inder engaging face, relative to the length of the tongues, that when the ring is Worn to the extent 0f the space originally existing between the line and cylinder engaging face, the tongues will still `be in overlapping relationship and leakage between the ends of thering will beprevented.

8. A piston packing comprisingV an-expansible smaller radius con-` on the end ofV each tongue` 10 opposite side face, and meeting one side face of the ring at a une spaced rom the cylinder engaging face a distance less than said thickness, so that after the ring is Worn to the extent of the space originally existing between said line and cylinder engaging face, said inner tongue will form a part of the cylinder engaging face I of the ring to prevent leakage between the ends of the ring during the further wear of the ring.

CLYDE C. FARMER. 

